Storm boosts Idaho snowpack

Tuesday , March 18, 2014 - 10:43 AM

Eric Barker

The storms of the past week have lifted some of Idaho's snowpacks from well below average to within a storm or two of normal.

On Monday, the mountains of the Clearwater River basin held a snowpack equal to 67 percent of the long-term average. By Friday, storms had dumped close to 3 feet of snow in many locations and jumped the snowpack to 88 percent of average. At Cool Creek, near the confluence of Kelly Creek and the North Fork of the Clearwater River, a remote weather station recorded 37 inches of new snow -- equal to 5.2 inches of water held in the snowpack. Lolo Pass saw 31 inches of snow, a net 4.2 inches of water.

"The high pressure ridge that had been blocking the weather systems from coming in finally moved on," said Ron Abramovich, a hydrologist with the Natural Resources Conservation Service at Boise. "The atmosphere was very active but the storms were going around us in the west. They were heading up to Alaska basically. Now it's our turn."

The Salmon River basin snowpack rose from 59 percent of average to 77 percent. But the Panhandle Mountains rose only 4 percentage points, from 84 percent to 88 percent.

The seven-day forecast calls for more snow and rain for the central Idaho mountains. Abramovich said if that happens it could leave snowpacks in much of Idaho near the long-term average for midwinter.

"It is just what we needed with the dry two months we had," he said. "We are back in the game now pretty much across most of the state."

Even with the ample precipitation of late, some mountain ranges are still well behind average. The snowpack in the mountains that feed the Grand Ronde, Powder, Burnt and Imnaha rivers rose from 51 percent to 71 percent, and the Lower Snake River basin sits at 83 percent of average, up from 62 percent at the start of the week. The Owyhee River basin in southwestern Idaho has a snowpack that is only 41 percent of average. But on Monday it was 17 percent of normal.

Mountain snowpacks feed spring runoff, which pushes juvenile salmon and steelhead toward the Pacific Ocean. Snow levels are watched by southern Idaho farmers who rely on runoff for irrigation water and by white-water rafters and kayakers who plan river trips.